When would you choose relational storage over a document database for a new application?

Start with data relationships, transaction boundaries, integrity requirements, query patte s, and operational skills. Relational storage often fits strongly related entities and cross-entity constraints, while a document model can fit independently accessed aggregates with evolving nested structure. Both categories have products with overlapping capabilities, so avoid claims that one cannot transact or scale. Prototype the hardest queries and updates, estimate data growth, and consider indexing, migrations, backups, and failure behavior. Choose based on concrete requirements rather than adopting a database because its category sounds newer.